EIGRP cannot access internet

[PengyuGuanAu]

Hi there,

my topology is ISP-->home wireless wifi-->Cisco (R1)-->Cisco (R2)--> Cisco (R3)

3 Cisco router running EIGRP, R1 can access internet, but R2 and R3 cannot access internet.

my understanding is redistribute a default network into EIGRP, 

I tried these configuration on R1, but still not working.

ip route 0.0.0.0 0.0.0.0 192.168.31.1. *this address is my home wireless wifi address*

 router eigrp 1

redistribute static

does anyone can give me some advise 

thanks 

jerry 

[balaji.bandi]

Since R1 can access Interenet because the R1 connected IP doing NAT (i guess here, that is the R1 get internet)

what IP address R2 and R3 have here ?

when you do trace-route from R3, that is the last router, where the trace-route stops ? is that reaches R1 ? (if that reaches R1 ?)

[Seb Rupik]

Hi there,

you must include metric values when redistributing a static route:

!
router eigrp 1
 redistribute static metric 100000 1000 255 1 1500
!

cheers,

Seb.

[Richard Burts]

@Seb Rupik has identified an important issue. Post the output of show ip route from R2 and R3 and check whether they are learning a default route. If not make sure that you do provide metrics for redistribution.

I believe there may be another issue. Am I correct in assuming that R1 connects to home wireless using one interface (and one subnet) and connects to R2 using a different interface (and a different subnet). If that is correct then attempts to access Internet from R1 would use source address of interface connecting to home wireless and home wireless would recognize this address and process the traffic. When R2 attempts to access Internet the source address would be in the subnet used for connecting the routers. When its traffic gets to home wireless would home wireless recognize that subnet and process its traffic? You may need some routing logic on home wireless to recognize and process traffic from the other subnet and may need some address translation logic on home wireless to recognize and process traffic from the other subnet.

[PengyuGuanAu]

Hi Rick,

thanks for reply. It is very cleared explanation.

yes, R2 and R3 using the different subnet.

I can see sh ip route on R2 and R3, these is a *EX route redistributed.

don’t know how to do the home wireless wifi yet.

Will working on it. 
a lot things need to learn 

[Richard Burts]

Thanks for the additional information. Just to clarify on R2 and R3 is the EX route redistributed for 0.0.0.0? If so that confirms that they are learning the default route.

In my previous response I had suggested that on home wireless you might need some routing logic for the subnets of R2 and of R3 and might need address translation for those subnets. And that suggestion is valid. But it occurs to me that there is an alternative which might be easier for you to implement. You could configure on R1 address translation for the subnets of R2 and of R3. If R1 is translating the addresses of R2 and R3 then home wireless would not see those subnets and would not need routing logic for them or address translation for them.

Yes there is a lot to learn. This community is an excellent place to ask questions and to learn about networking. I hope to see you continue to be active in the community.

[Georg Pauwen]

Hello,

in addition to posting the R1 router configuration, also indicate which additional subnets you want to access the Internet...

[balaji.bandi]

On another note, as i have asked if the R3 can reach until it fails, then If you can do it on R1 NAT is a good place to start.

as i suggested we need to know how the routing each device learning R3 has reachability to go to Home broadband router.

[Asadullah Oryakhil]

Thanks i have same problem  it is working 

[Richard Burts]

Thanks for sharing your experience. Yes doing NAT is an important part of getting Internet access.

[Georg Pauwen]

Hello,

try:

ip route 0.0.0.0 0.0.0.0 192.168.31.1

!

router eigrp 1

network 0.0.0.0

to get the default routes into the EIGRP process. That said, your issue is more likely related to NAT. Can you post the running config of your R1 router ?

[Giuseppe Larosa · Accepted solution]

Hello @PengyuGuanAu ,

a default route is not enough to access the internet if you are using private IP addresses like

10.0.10.0/24  or 172.16-31.x.0/24 or 192.168.x.0/24 all these are in RFC 1918 private IPv4 addresses

I guess you are currently doing NAT on your home router for only the subnet directly connected 192.168.31.0/24 or similar.

Either the home router is / can be configured to NAT also for internal networks on R2 and R3,  but not all home routers allow this, or you need to configure NAT on R1 so that source IP addresses from internal subnets are translated to R1 IP address to home router.

Hope to help

Giuseppe